Implantable microstimulators have been developed to provide therapy for a variety of disorders, as well as to provide other treatments. For example, implantable microstimulators can be used in neurological therapy by stimulating nerves or muscles, for urinary urge incontinence by stimulating nerve fibers proximal to the pudendal nerves of the pelvic floor, for erectile and other sexual dysfunctions by stimulating the cavernous nerve(s), for reduction of pressure sores or venous stasis, etc.
Implantable microstimulators, such as the BION® device (available from Advanced Bionics Corporation, Sylmar, Calif.), have exposed electrodes and a small, often cylindrical, housing that contains the electronic circuitry and power source that produce electrical pulses at the electrodes for stimulation of the neighboring tissue. It is preferable that the electronic circuitry and power source be held within the housing in a hermetically-sealed environment for the protection of the user and the protection of the circuitry and power source. Once implanted, it is often preferable that the microstimulator can be controlled and/or that the electrical source can be charged without removing the microstimulator from the implanted environment.
These cylindrical devices are typically implanted using a surgical tool that includes a blunt dissector. An insertion passage inside the human body is created using the blunt dissector. The dissector may be connected to an external electrical pulse generator to assist in identifying the location of the target tissue. To implant the microstimulator, the blunt dissector tool must be withdrawn and the microstimulator inserted through the passage created by the tool. It can be difficult, however, to maintain the position of the tool during the exchange of the dissector and the microstimulator. During this exchange, the exact location of the target tissue, such as a nerve, can be lost and then the process must be repeated using the dissector.
Furthermore, the small size of the microstimulator can make it difficult to extract the implanted microstimulator from the human body, when desired (for example, when the battery is no longer usable or when there is no further need for the device.) Typically, a cut-down procedure or a large diameter tool is used to locate the microstimulator and remove it from the tissue. This can be damaging to the tissue and its surroundings.